The present invention relates to seat belt devices for protecting automobile passengers during collisions, and more particularly, to an air belt device having a bag-like portion, which is inflated by a gas generator. Further particularly, the present invention pertains to an air belt device that copes with erroneous functioning of a gas generator.
Japanese Unexamined Patent Publication No. 5-85301 describes a prior air belt device. FIG. 6(a) shows a perspective view of the air belt device. FIG. 6(b) shows a cross-sectional view of the air belt device taken along line B--B in FIG. 6(a).
As shown in the drawings, an air belt 1 includes a shoulder belt 2, a lap belt 3, a buckle 4, a tongue 5, and an intermediate guide 6. The shoulder belt 2 extends diagonally from the right side of a passenger to the left side of the passenger. The lap belt 3 extends from the right side of a passenger to the left side. The buckle 4 is arranged, for example, on the vehicle floor. The tongue 5 is engaged with the buckle 4 when fastening the seat belt. The intemediate guide 6 guides the shoulder belt 2.
The shoulder belt 2 includes a normal belt 2a which is an ordinary seat belt, and a bag-like belt 2b, which is connected to one end of the normal belt 2a. The normal belt 2a slides freely through the intermediate guide 6. The other end of the normal belt 2a is connected with a seat belt retractor 7 having an emergency lock system (ELR)mechanism. The normal belt 2a is wound into the seat belt retractor 7.
The bag-like belt 2b is located at a portion that contacts a passenger and is connected with one end of the tongue 5. The opposite end of the tongue 5 is not connected with the normal belt 2a.
The lap belt 3 is formed by a normal belt, which is an ordinary seat belt. One end of the lap belt 3 is connected with the tongue 5. The other end of the lap belt 3 is connected with the seat belt retractor 8 (ELR) . The buckle 4 is connected with a gas generator 9, which generates high pressure gas during emergencies, such as when a collision occurs.
The gas generated by the gas generator 9 flows toward the bag-like belt 2b through a passage extending through the tongue 5 and the buckle 4.
The bag-like belt portion 2b of the shoulder belt 2 has a body 2c. The body 2c, for example, may be folded and covered by a cover 2d, as shown by the solid line in FIG. 6(b). The sides of the cover 2d are sewed to each other such that a stitching 2e is formed. This keeps the shoulder belt 2 in a strip-like state under normal situations. The stitching 2e of the cover 2d is easily opened by the inflation force of the shoulder belt 2 when the gas generator 9 is actuated. The bag-like belt 2b inflates, as shown by the dashed line in FIG. 6(b).
In the prior air belt device 1 described above, if the gas generator 9 is actuated when the tongue 5 is not inserted in the buckle 4, the generated gas is discharged upward from the buckle 4.